I use Canidae, for the large dogs and Purina One for Pepper.
Nutro is a very good food too.
Ashley, their might have been a little
opening in the bag you bought, and possibly some moisture got in and bugs laid eggs etc. If the bag was not stored or
properly handled after it left the manufacturer.
I would not give up on Purina One if you like it,
but I would complain to the store where you bought it from.

(I always check experations dates and make sure the bag
is perfectly sealed before I purchase the dog food
bag from the Pet store)

Just takes a tiny hole for bugs to get in.
I would have been grossed out if I saw that.
I once bought wild bird feed and I stored the left
over feed in a non air tight container.
I ended up with little moths flying all over the house. : (
I now store all my pets food in air tight containers.